Postbag

dev.postbagPublished by postbag.devv0.1.1Updated Oct 24, 2026

Form backend that routes: one tool per Postbag API operation, plus quickstart and explain.

VerifiedSTDIODesktop onlyProductivity & Workflow Business & Commerce

Server details

Identifier: dev.postbag/mcp
Transport: STDIO
Runtime: Desktop only
Trust: Verified
Published: Sep 16, 2026

Security note

MCP servers receive tool arguments from a conversation and may perform external actions. Review what a server can do before you enable it, and give it only the access it needs.

The registry verified that this server's namespace belongs to postbag.dev. It runs from a package rather than a hosted endpoint, so there is no endpoint to match against that domain.

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Overview

AI-generated overview

Postbag's local MCP server exposes its form-backend API so an assistant can manage form endpoints, submissions and routing to email, webhooks or CRM.

What you can do: Manage form endpoints and their submissions through one tool per Postbag API operation
Route incoming form data to destinations such as email, Telegram, webhooks, partners or a CRM
Group many forms into one stream and map differing fields onto a single shape
Get quickstart guidance and explanations of Postbag concepts from the assistant
When to use it: Useful when you build or maintain websites with HTML forms and want an assistant to wire up endpoints, inspect submissions, or set up routing and digests without leaving the chat.
Requirements: Runs locally over stdio via npx from the npm package @postbag/mcp, so Node.js is needed. Requires a Postbag API key in the POSTBAG_API_KEY environment variable (live or test key). POSTBAG_API_URL is optional and only needed for a self-hosted instance. Network access to the Postbag API.

Before you install

The API key in POSTBAG_API_KEY grants access to your Postbag account and form data; keep it out of shared configs. Tools can create and change endpoints, routing rules and delivery settings, and may read real submissions containing personal data. Submissions are forwarded to third-party destinations such as email, Telegram, webhooks or a CRM.

Installation

In SourceWeft

Open Postbag in the dashboard and add it to a workspace.
Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

Postbag

[CI] [npm: postbag] [npm: @postbag/sdk] [npm: @postbag/mcp] [License: AGPL-3.0] [skills.sh]

A form backend that routes. Point any HTML form at a Postbag endpoint and it lands in your inbox — then goes wherever it should: email, Telegram, a webhook, a partner, your CRM. Built for people who run many sites, and for the AI agents that build them.

html

<form action="https://api.postbag.dev/s/fm_8f3kq2" method="POST">  <input name="email" type="email" required>  <textarea name="message"></textarea>  <button>Send</button></form>

<form action="https://api.postbag.dev/s/fm_8f3kq2" method="POST">  <input name="email" type="email" required>  <textarea name="message"></textarea>  <button>Send</button></form>

That's the whole integration for one form. Everything else — grouping forty forms into one stream, mapping their different fields onto one shape, sending that shape to a partner between two dates, a daily digest, never losing a submission — is there when you need it and invisible when you don't.

New here (human or AI agent)? Read CLAUDE.md first.

Why it exists

Every website has forms. Every form needs somewhere to go. Formspree and friends solve "somewhere" for one site; they fall over when you have fifteen sites feeding one partner with fifteen slightly different forms. Postbag is the source of truth for what each form collects, what each downstream system receives, and the versioned contract between them.

The one idea

The database makes it correct; events make it fast.

A submission is accepted the instant it is a row. Delivery is a durable outbox that a worker drains with retries. Realtime nudges are an accelerator, never a transport. If every event stream in the system died, every submission would still arrive — late, never lost. (Inherited from the lead pipeline this generalises; see docs/ARCHITECTURE.md.)

Status

Phase 1 — MVP live at postbag.dev (site, docs, dashboard at /app, API at /v1). See PROGRESS.md for the live blueprint and docs/ROADMAP.md for phases.

Documentation

Start at docs/README.md.

License

The server, dashboard, site and domain packages (apps/*, packages/core, packages/db, packages/auth) are licensed under AGPL-3.0. The client packages that run inside your own code — @postbag/sdk, the postbag CLI and @postbag/mcp — are MIT. Rationale in ADR-006.

Source: README.md at commit 192e431

Tools

SourceWeft has not started this package in its sandbox yet, so its tools are not known.

Version history

v0.1.1LatestSep 16, 2026

Score

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